The most commonly available forms of natural and imitation cheese sauces (collectively “cheese sauces”) or pudding products presently produced for commercial sale in the United States market are “low acid” food products, as defined in 21 C.F.R § 114.3(d), which have a pH of greater than 4.6. Cheese sauces of the “low acid” category typically have a protein content of between 1% and 5% by weight, or more. Although use of protein components in cheese sauces greatly increases their production cost, it is generally considered in the industry that such high protein contents are necessary to produce a cheese sauce that has a body, mouthfeel, and flavor comparable to cheese sauces containing natal cheese. Thus, it is viewed that high protein content is a requisite to production of a cheese sauce acceptable to the consumer palate.
The conventional low acid cheese sauces presently available offer the consumer a good dairy-like taste, body, and mouthfeel, but because of their low pH, they can easily become spoiled by microbial growth and create an unpleasant and potentially dangerous culinary experience for the consumer if handled or packaged improperly. To reduce the potential for bacterial spoilage, government regulations pertaining to food safety require that low acid products, such as conventional low acid cheese sauces, must be subjected to severe heat sterilization procedures under conditions sufficient to kill C. botulinum and other pathogens.
Commonly used methods of preservation or means to control development of pathogens in a low acid product include aseptic, retort and hurdle processing methods, as well as control of pathogen growth by low water activity. Both aseptic processing and retort processing require heating the product to high temperatures (around 120° C.-148° C. or 250° F.-300° F.) to accomplish sterilization. The equipment used for these processes is expensive, and costly to operate and maintain. In addition, high temperature processing can result in what is referred to in the industry as “burn-on,” linescale, or fouling of the product, where commercially unacceptable, burned, overcooked, or stale taste is imparted to the cheese sauce or pudding. Fouled product is unsaleable and is therefore discarded, resulting in waste of materials and labor. Accordingly, the productivity of the manufacturing process is decreased.
Even if heat sterilization does not result in degradation of non-hurdle low acid product, processed low acid food products, such as cheese sauces and puddings, must be retained by the manufacturer, by law, for an incubation period prior to release to the consumer, because of the potential for bacterial spoilage. The finished packaged product must be held in incubation for a minimum of approximately ten days before shipping in order to verify that the selected sterilization process was adequate and to evaluate the likelihood of subsequent on-shelf spoilage.
In the case of some conventional cheese sauces, bacterial stability is most often achieved though use of what is known in the art as “hurdle technology,” a combined effect of carefully restricted levels of pH, moisture (water activity aw), and salts (emulsifier phosphates and NaCl) in the processed cheese composition. Hurdle technology and its applications in the area of food preservation are well known and documented in the art, e.g., Tanaka, J. Food Protect., vol. 49, no. 7, pp. 526-531 (July 1986), the contents of which are incorporated herein by reference.
In contrast to the conventional low acid cheese sauces and pudding products discussed above, “acidified” foods, as defined in 21 C.F.R. § 113.4(a), require neither a pre-shipment incubation period, application of costly sterilization techniques, nor are they restricted by the limitations of hurdle technology, because microbial growth is retarded in the acidic environment of a pH of not greater than 4.6 (i.e., 4.6 or less).
Because of the numerous safety, regulatory, and manufacturing advantages of high acid or “acidified” food products, significant efforts in the food industry have been directed toward attempts to develop an acidified composition suitable for use as a cheese sauce or pudding product that resembles, in taste, texture, and organoleptic properties, the conventional low acid cheese sauces or puddings presently on the market. Such an acidified food composition would have the benefit of being safer than conventional low acid cheese sauces or puddings, because the acidic pH is sufficient to retard the growth of microbial pathogens, even in the absence of heat sterilization. In addition, the processing costs would be less for an acidified cheese sauce or pudding, because it would not have to be heated to temperatures as high as its low acid counterparts, thereby reducing utility costs and increasing productivity by eliminating fouling or degradation of product quality. Moreover, an acidified composition would not require an incubation period and, because of the minimal processing required, would be compatible with more types of packaging and processing equipment than the conventional low acid cheese sauces or puddings.
However, prior attempts to produce an acidified cheese sauce or pudding product, i.e., one having a pH of not greater than 4.6, were accomplished by adding quantities of food grade acidulants to conventional low acid cheese sauce formulations. Because the conventional low acid formulations often contain significant quantities of proteins, such as milk proteins, whey proteins, and natural cheese solids (often as high as 5% by weight), and/or buffering emulsifiers, such as salts of citrates and phosphates, the amount of acid necessary to arrive at a pH of not greater than 4.6 resulted in products having a total titratable acid (“TTA”) level of approximately 1.0% to 2.5%. The resulting cheese sauces were acidified, but because of the high acid content as measured by the TTA, they do not have the same savory and cheese-like tastes as the conventional low acid cheese sauces. Instead they are characterized by unpleasant sour, tart, and acidic notes and are therefore commercially unacceptable without the addition of flavor-imparting substances, such as tomatoes, onions, peppers, and smoke flavors, to mask the unacceptable tastes.
Consequently, there remains a need in the food industry for an acidified food composition useful in the manufacture of cheese sauces, puddings, or other cheese products, which possesses a flavor, texture, and consistency as good as or superior to conventional low acid cheese sauces or puddings, yet, by virtue of its acidic pH, is shelf stable and resistant to microbial growth.